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Soil Nitrogen Availability after Long‐term Continuous No‐tillage and Conventional Tillage Corn Production
Author(s) -
Rice C. W.,
Smith M. S.,
Blevins R. L.
Publication year - 1986
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1986.03615995005000050023x
Subject(s) - tillage , loam , mineralization (soil science) , conventional tillage , agronomy , soil water , fertilizer , zoology , nitrogen , environmental science , chemistry , soil science , biology , organic chemistry
Several short‐term studies of no‐tillage (NT) vs. conventional tillage (CT) have suggested that N availability is lower in NT. Less is known about the long‐term effects of NT on soil processes and N availability. Recent observations of a NT vs. CT experiment, initiated in 1970 on a Maury silt loam (Typic Paleudalfs), are presented here. During the first 9 yr of this study corn ( Zea mays L.) yields with no N fertilizer were consistently greater in CT than NT, but at high N rates yields were approximately equal. Since 1979, there have been no consistent differences between the tillage systems with regard to yield without N or in relative response to N. Inorganic soil N during 1981 and 1982 was usually equal but occasionally greater in NT compared to CT, in contrast to previous observations during the early years of this experiment. Soil N mineralization was estimated in 1982 by a laboratory soil core incubation technique and by observing dilution rates of labeled N added to field microplots. Both of these approaches suggested that N mineralization was at least as great in long‐term NT plots as in long‐term CT plots. We suggest that the lower availability of N frequently observed in NT soils, in some cases can be a transient effect. In this experiment availability of soil N in NT apparently approached that of CT after approximately 10 yr.